ON ALLY CAST: Elphrihaim enshrouds the target ally with warmth, healing them over 8 seconds.
ON ENEMY CAST: Elphrihaim has a pair of fireballs charge around the target enemy, slowing them for 3 seconds and dealing damage afterward.

FIRST CAST: Elphrihaim begins charging up a fireball, increasing in damage and range. After 4 seconds, all attributes are maximized.

While preparing, Elphrihaim cannot auto-attack or use other abilities, and his Movement Speed is reduced by 35%. After 8 seconds, Fireball Crash is automatically cancelled and half the mana cost is refunded.

SECOND CAST: Elphrihaim launches the fireball to the target point, dealing Magic Damage in an area, slowing all enemies hit by 20-60% (depending on time spent charging) for 3 seconds.

ACTIVE: ON ENEMY CAST: Elphrihaim creates a rune of fire on the target for 5 seconds, dealing magic damage in a 350 unit radius each time they suffer damage.
ON ALLY CAST: Elphrihaim blesses the target ally with fire for 10 seconds, causing their basic attacks and ability damage to inflict magic damage over 3 seconds.

Elphrihaim marks the ground with runes, causing it to erupt in flames for 4 seconds. The cooldown and mana cost of this ability is based on how much area is covered. This ability only activates on-ability-cast effects if more than 500 area is covered. (if only a dot is made, this ability will generate a circular AoE with 235 diameter)

Magic Damage per second: 25 / 40 / 55 (+25% Ability Power)

AoE radius: 100

Quotes

Has two voices-- a slightly more firey one, used when Espadi is prepared.
This voice is also used exclusively if the line is in square brackets.

Upon selection

"I will emblazon our sign on the enemy."

Attacking

"Ignition!"

"Flame's on you!"

"Freeze...?"

Movement

"Your command draws me like a moth."

"It shall be.. as you say."

"Light the way."

[After standing still for 15+ seconds first]

"Much better, I felt frozen!

Taunt

[I am the radiant dawn, the bringer of fire to all-- and you are the darkness!]

Joke

"I am your flame, your cursor is my wick."

Other stuff

This is FIAAAAAAAAAARRRRRRRR.
Ephri is all about fire. Ideally, his passive would alight his sword on fire and have him cut such that the flames leap off of his sword and onto the enemy... ala http://lparchive.org/Fire-Emblem-Sword-of-Seals/Update%2068/24-SoSranged.gif .
As a caster, he wants to get as much AP as possible, as fast as possible. However, he is not a super-long range caster, nor is he a far ranged attacker. An obvious chose for build is Lich Bane (re: that means you will have an additional +100% AP scaling on your abilities, since your passive is basically a lich bane Unique)

Something along the lines of Morellonomicon, Athene's, Sorcerer's Shoes, Rylai's, Liandry's and Lich Bane is my current theory build. :P